Electrodeposition of organic material



April 26, 1932. s. E. SHEPPARD ET AL ELECTRODEPOSITION OF ORGANIC MATERiAL Filed April 5, 1926 2 Sheets-Sheet 1 Fla a. 12 1.5 10

LBeaL,

NVENTORS,

ELECTRODEPOSITION OF ORGANIC MATERIAL Patented Apr. 26, 1932 UNITED STATES PATENT OFFICE SAMUEL E. SHEPPARD CARL L. BEAL, OF ROCHESTER, NEW YORK, ASSIGNORS, BY MESNE ASSIGNMENTS, TO AMERICAN ANODE, INC., A CORPORATION OF DELAWARE ELECTRODEPOSITION OF ORGANIC MATERIAL Application filed April 5,

This invention relates to an improvement in the process of electrodeposition of an organic material and more particularlyto the deposition of rubber from an aqueous emulsion, as described in the patent to Sheppard and Eberlin, No. 1,476,374, granted Decemher 4, 1923.

We have discovered that, for certain purposes, considerable advantages may be derived by continuously cooling the anode upon the surface of which organic material is being deposited. The local heat generated at the electrode in process of deposition is removed as fast as it is generated. 9

We have found that material deposited under such conditions is particularly plastic and soft. Where it is desired that the de-. posited layer'should be heavy and thick, or that it should retain suflicient-plasticity to be moulded, the cooling of the anode is particularly desirable. We have found that, other things being equal, the lower the temperature at which the electrodeposition is made, within practicable limits, the softer and more plastic is the deposit obtained.

The process is applicable not only to the rubber emulsions described in the patent mentioned but also to @mixed emulsions 'of rubber and cellulosic and other organic materials and to aqueous emulsions or organic materials as described in the applications of Sheppard and Eberlin, Serial Numbers 611,162, filed Jan. 6, 1923; 16,572, filed Mar. 18, 1925;'18,304, filed Mar. 25, 1925; 21,339, filed Apr. 7 1925; 21,341, filed Apr. 7, 1925, and 35,613, filed June 8, 1925. It is equally applicable to the formation of removable coatings or films and of permanently adherent coatings or platings, certain apparatus and processes in which it may be incorporated being shown in the application of Sheppard and Eberlin, Serial No. 70,321, filed Nov. 20, 1925, and that of Sheppard and Real, 88,955, filed Feb. 17, 1926, in the last mentioned of which, covering a different invention, certain applications ofour invention are shown but the invention is not generically claimed.

It is possible with a temperature main- 2 tained well below to plate out deposits 1926. Serial No. 99,846.

at least two or three times as thick as when no cooling is employed. The deposited rubber after drying and vulcanization, particu larly ifcompacted as described in applications Serial No. 70,321 and 88,955, is more uniform and compact. The rationale of the cooling effect appears to consist in lessening the tendency of syn'aeresis (shrinkage with exudatlon of water and serum) of the coalesced part1cles of rubber latex or emulsion.

Such shrinkage lessens the conductivity of the coating and forms an insulating body over the anode. The porous condition, however, is favorable to the maintenance of electrio conductivity, and permits the building up of thick plastic layers, while local strains and tensions are minimized.

Of course, if a thin dense layer is desired, the cooling step would not be utilized and in such cases the heat may even be so great as to cause partial vulcanization at the anode. The exact temperature yielding the best result will, of course, vary with the emulsion used and will also be dependent upon the nature of the layer desired and the purpose for which it is intended. In general it may be stated that, for most purposes, we have found it satisfactory to maintain the temperature below 50-.F. and above the freezing point of the emulsion which is usually somewhat below 32 F.

There will now be described certain apparatus by which our improved process may be advantageously carried out, reference being made to the accompanying drawings, wherein the same reference characters denote the same parts throughout and in which,-

Fig. 1 illustrates in section a very simple embodiment of such apparatus;

, Fig. 2 is a perspective view of the cooled anode used in the form shown in Fig. 1;

Fig. 3 shows in longitudinal section apparatus for forming tubes and embodying our invention 3 Fig. 4 is a transverse section of such apparatus;

Fig. 5 is a view in cross section of the oathode-anode assembly, taken on line 5-5 of Fig. 4.

Fig. 6 is a view in longitudinal section of another apparatus for forming tubes;

Fig. 7 is a transverse section on line 77 of Fig. 6;

. Fig. 8 illustrates diagrammatically another ap aratus for carrying out our invention;

igs. 9, 10 and 11 illustrates still further embodiments.

-It is to be understood that in all of the figures, the showing is purposely largely diagrammatic, in order that the relation of parts vital to an understanding of our invention may be clear, without being obscured by details of mechanism not a part of our invention.

In the simple embodiment used in Fig. 1 to illustrate our invention, 1 is a tank containing an emulsion 2 of the type discussed. In

the tank are suspended a cathode, shown formally at 3, and a hollow anode 4, here shown as a rectangular box 5 having inlet and outlet pipes 6 and 7, through which a cooling fluid, either liquid or gaseous, may be circulated. In practice, brine is found to be very satisfactory. All of the sides but one of this box and the connections thereto are insulated or made of non-conducting material and the excepted side 8 is of metal and connected with a positive source of electric potential. Upon this side 8 a layer 9 of electrodepositable material is formed.

In Figs. 3 to 5 is shown an apparatus particularly designed for the formation of tubes, such as the inner tubes for tires. In a tank 10, containing an emulsion 11, are suspended from racks 12 and 13 respectively suitably shaped anodes 14 and cathodes 15. The anodes are formed of metal tubes bent nearly to form circles and open slightly at the top, where they are joined by connections 26 with pipes 27 by means of which a cooling fluid is circulated through the anodes. On each side of each anode 14 is a cathode 15 which is bowed in cross section so as partially to surround the anode, as shown in Fig. 5, and which is also of nearly circular shape as shown in Fig. 4. The racks supporting the electrodes are supported by cords 17 from supports 18, whereby they may be raised from the tank. Rotary stirrers 19 are supported in the circulatory system 20 on shafts 21 and are driven from the belts 22 and pulleys 23 to keep the emulsion in circulation. An additional removable central cathode 24, shown only in Fig. 4, may be used to insure reinforcement by heavier plating on the inner side of the tube.

After deposition of the rubber, the forms are lifted and disconnected from the pipes 17. The tubes are dried and vulcanized on the forms and are then stripped off. The ends may be vulcanized together and the valve stems cemented or secured in place in the usual way.

The apparatus shown in Figs..6 and 7,

comprises a long tank 29 containing an emulsion bath 28 in which are supported long tubes 30 connected at one end by rotatable connections 31 with the tubular supports 32, connected to an outlet pipe 33 supported on a frame 34 suspended by cord 35 from a support 36. At the other end the tubes 30 are connected at 37 with rotatable tubular supports 38 which are turned by the worm gears 39 driven by shaft 40, pulley 41 and belt 42. The tubular supports 38 are rotatably connected with and supported by the inlet system 43. These parts are carried by a frame 44 suspended by cord 45 from support 46. The frames and the parts supported thereby can thus be lifted clear of the tank. On each side of the tubes 30 is suspended vertically a wire screen 47 constituting a cathode. At each end of the tank is an additional refrigerating unit 48 with pi cs 49 for the circulation of the chilling uid. There is further provided a circulatory system 50 including a pump 51 by which the emulsion is kept in circulation.

In use the pipes 30 will be lifted from the tank and the unit as a whole placed in a curing chamber and the deposited rubber tubes finally stripped from the tubes 30.

This process is applicable to the electrodeposition of a rubber sheet on a continuously moving anode, upon fabric or as a coat ing on a metal band as disclosed in the copending applications and in the following types of apparatus.

In Fig. 8, is shown an apparatus, also 100 shown in our application Serial No. 88,955.

In the tank is rotated a drum 61 having a metal surface and constituting the anode.

A cathode shown formally at 62 depends in the emulsion bath 63. Around the tank is a 105 jacket 64 by which the temperature of the unit as a whole, including the anode, may be regulated. The deposited sheet 65 is continuously stripped from the moving anode surface, and directed over guide roller 66 110 through a drier 67 where it is partially dried, then between calendar rolls 68 to the final curing apparatus comprising a drying compartment 69 and vulcanizer 7 Oto a take-up roll 71.

In Fig. 9, a hollow rotating drum anode 72 is journaled on tubular supports 73, connected to a pipe 74 for the entrance of a cooling fluid. The supports 73 are held in the walls of tank 75 containing an emulsion 76 of the 120 type specified.

In Fig. 10, the drum 72 constructed and supported as in Fig. 9 serves as a guide around which passes the metal or fabric band 77 upon which the layer 7' 8 is. deposited 125 as. described in our application, Serial No. 88,955.

In F ig. 11, a hollow metal form 80 in the shape of a hand, having a pipe system 81 for introducing a cooling fluid into its ex- 130 tremities and an exit pipe 82, is suspended in a bath 83 of emulsion in a tank 84, and constitutes the anode. Suitably shaped cathodes are suspended in the bath and are indicated formally at 85. Such anodes will be used for. making rubber gloves which will be cured on the forms and readily stripped therefrom.

We do not in any way limit ourselves to a particular emulsion. or to a particular ma- It is apparent that numerous embodiments of our invention are possible and we contemplate as indicated within our invention all such modifications and equivalents as fall within the scope of the appended claims.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. In the process of depositing a layer of an organic material on an electroconducting surface which includes bringing said surface into contact with an electroconducting aqueous emulsion of such material and passing a depositing electric current through said surface and emulsion, the step of removing the heat liberated in the process of electrodeposition at such surface.

2. In the process of depositing a layer of an organic material on an electroconducting surface which includes bringing said surface into contact with an electroconducting aqueous emulsion of such material and passing a depositing electric current through said surface and emulsion, the step of continuously conducting away from such surface the heat generated in the process of electrodeposition.

3. In the process of forming a layer of an organic material that comprises bringing a surface of a metallicbody into contact with an electroconducting aqueous emulsion of such material and passing a depositing current through said body and emulsion, thestep of passing a cooling fluid continuously across and in contact with another surface of such metallic body. v

4. In the process of depositing rubber on an electroconducting surface which includes bringing said surface into contact with an electroconducting rubber emulsion and passing a depositing electric current through said surface and emulsion, the stepof cooling the zone including the area of deposition to maintain it at a temperature substantially below room temperature.

5. In the process of depositing rubber on an electroconducting surface which includes bringing said surface into contact with an electroconducting rubber emulsion and passing a depositing electric current through said surface and emulsion, the step of maintaining the zone including the area of electrodeposition at a temperature less than 50 F. I

6. The process of electrodepositing on an electrodic surface a layer of a substantially electrical non-conductive composition from an aqueous dispersion thereof which comprises preparing an electroconducting dispersion of the non-conductive composition, bringing said surface into contact with the dispersion, passing a depositing electric current through said surface and dlspersion, and retaining electroconductivity through the deposited non-conductive composition by maintaining the composition at a relatively low temperature.

Signed at Rochester, New York, this 31st day of March, 1926.

' SAMUEL E. SHEPPARD.

CARL L. BEAL. 

